oa Biochemical response and effects of bariatric surgeries on type 2 diabetes

Background and Objectives: Bariatric surgery has proved to be a powerful technique that not only induces drastic and long-lasting weight loss but, also resolves type 2 diabetes and potentially reverses diabetes-related diseases in morbidly obese patients. Extraordinarily, the remission of type 2 diabetes occurs long before any significant weight loss. The physiological and biochemical mechanisms underlying the astonishing impact of bariatric surgery on glucose homeostasis are, however, poorly understood. Our objective is to use mathematical modeling to try to better understand the mechanisms behind type 2 diabetes remission after bariatric surgery. Methods: A general mathematical method is proposed for estimating the biochemical response to pharmaceuticals, surgeries, or other medical interventions. This method is then applied in an extremely simple model of the response to Roux-en-Y gastric bypass surgery and related procedures. Results and Conclusions: There are clearly multiple and quite complex effects of bariatric surgeries. The results of our model confirm that the remission of type 2 diabetes after bariatric surgery can be largely explained by the enhanced post-meal excretion of glucagon-like peptide-1 (GLP-1), an incretin that increases insulin secretion and has been shown to increase proliferation and decrease apoptosis of pancreatic beta cells, but it also suggests that other mechanisms are likely to be involved, possibly including an additional insulin-independent pathway for glucose transport into cells.